Today's mobile electronic devices are capable of performing a wide variety of functions. For example, “smartphones” are mobile devices that combine wireless communication functions with other functions, such as mapping and navigation using a global positioning system (GPS), wireless network access (e.g., electronic mail and Internet web browsing), digital imaging, digital audio playback, personal digital assistant (PDA) functions (e.g., synchronized calendaring), and the like. Although many mobile devices are hand held, they can also have a larger form factor. For example, they may take the form of tablet computers, laptop computers, portable gaming devices, or other similar electronic devices capable of remote communication. A common feature of smartphones and other similar mobile devices is a built-in digital camera for receiving and recording image data. In addition to capturing photographs, the digital camera can be used as a generic visual input device, thus greatly expanding the capability of the mobile device.